IEC 60445:2017
(Main)Basic and safety principles for man-machine interface, marking and identification - Identification of equipment terminals, conductor terminations and conductors
Basic and safety principles for man-machine interface, marking and identification - Identification of equipment terminals, conductor terminations and conductors
IEC 60445:2017 applies to the identification and marking of terminals of electrical equipment such as resistors, fuses, relays, contactors, transformers, rotating machines and, wherever applicable, to combinations of such equipment (e.g. assemblies), and also applies to the identification of terminations of certain designated conductors. It also provides general rules for the use of certain colours or alphanumeric notations to identify conductors with the aim of avoiding ambiguity and ensuring safe operation. These conductor colours or alphanumeric notations are intended to be applied in cables or cores, busbars, electrical equipment and installations. This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.
It has the status of a basic safety publication in accordance with IEC Guide 104. This sixth edition cancels and replaces the fifth edition of IEC 60445, published in 2010. This edition includes the following significant technical changes with respect to the previous edition:
a) the text of the introduction has been moved into the scope in accordance with IEC Guide 104;
b) colour codes for the identification of line conductors of DC systems;
c) colour code for the identification of functional earthing conductor;
d) update of Table A.1with colour codes for DC line conductors;
e) conversion of notes containing non-mandatory requirements to normative text;
f) the terminology is aligned with IEC 60050-195.
The contents of the corrigendum of November 2017 have been included in this copy.
Principes fondamentaux et de sécurité pour les interfaces hommes-machines, le marquage et l’identification - Identification des bornes de matériels, des extrémités de conducteurs et des conducteurs
L'IEC 60445:2017 s'applique à l'identification et au marquage des bornes de matériels électriques, tels que résistances, coupe-circuits à fusibles, relais, contacteurs, transformateurs, machines tournantes et, chaque fois que cela est possible, à des combinaisons de tels matériels (par exemple des ensembles) et s'applique aussi à l'identification des extrémités de certains conducteurs désignés. Il prévoit également des règles générales concernant l’utilisation de certaines couleurs ou de certains caractères alphanumériques pour identifier les conducteurs dans le but d’éviter toute ambiguïté et de garantir la sécurité de fonctionnement. Ces couleurs ou ces caractères alphanumériques destinés aux conducteurs doivent être appliqués aux câbles ou aux noyaux, aux barres omnibus, aux matériels et aux installations électriques.
Elle a le statut d'une publication fondamentale de sécurité, conformément au Guide 104 de l’IEC.
Cette sixième édition annule et remplace la cinquième édition de l’IEC 60445, parue en 2010.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) le texte de l’introduction a été déplacé dans le domaine d’application conformément au Guide 104 de l’IEC;
b) codes couleur permettant l’identification des conducteurs de ligne dans les systèmes à courant continu;
c) code couleur permettant l’identification d’un conducteur de mise à la terre fonctionnelle;
d) mise à jour du Tableau A.1intégrant les codes couleur des conducteurs de ligne à courant continu;
e) conversion des notes comportant des exigences non obligatoires en texte normatif;
f) la terminologie est alignée sur l’IEC 60050-195.
Le contenu du corrigendum de novembre 2017 a été pris en considération dans cet exemplaire.
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IEC 60445 ®
Edition 6.0 2017-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
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BASIC SAFETY PUBLICATION
Basic and safety principles for man-machine interface, marking and
identification – Identification of equipment terminals, conductor terminations
and conductors
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IEC 60445 ®
Edition 6.0 2017-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
BASIC SAFETY PUBLICATION
Basic and safety principles for man-machine interface, marking and
identification – Identification of equipment terminals, conductor terminations
and conductors
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 01.080.20; 13.110; 29.020 ISBN 978-2-8322-4717-4
– 2 – IEC 60445:2017 RLV © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Methods of identification . 9
5 Application of identification means . 10
6 Identification by colours . 10
6.1 General . 10
6.2 Use of single colours . 11
6.2.1 Permitted colours. 11
6.2.2 Neutral or mid-point conductor . 11
6.2.3 Line conductor in AC system . 11
6.2.4 Line conductor in DC system . 11
6.2.5 Functional earthing conductor . 11
6.3 Use of bi-colour combinations . 11
6.3.1 Permitted colours. 11
6.3.2 Protective conductor . 11
6.3.3 PEN conductor . 12
6.3.4 PEL conductor . 12
6.3.5 PEM conductor . 13
6.3.6 Protective bonding conductor. 13
7 Identification by alphanumeric notation . 13
7.1 General . 13
7.2 Equipment terminal identification – Marking principles . 14
7.3 Identification of certain designated conductors . 16
7.3.1 General . 16
7.3.2 Neutral conductor . 16
7.3.3 Protective conductor . 16
7.3.4 PEN conductor . 17
7.3.5 PEL conductor . 17
7.3.6 PEM conductor . 17
7.3.7 Protective bonding conductor. 17
7.3.8 Protective bonding conductor earthed . 17
7.3.9 Protective bonding conductor unearthed . 17
7.3.10 Functional earthing conductor . 17
7.3.11 Functional bonding conductor . 17
7.3.12 Mid-point conductor . 17
7.3.13 Line conductor . 17
Annex A (informative) Colours, alphanumeric notations and graphical symbols used
for identification of conductors and terminals . 18
Annex B (informative) List of notes concerning certain countries . 20
Bibliography . 26
Figure 1 – Single element with two terminals . 14
Figure 2 – Single element with four terminals: Two endpoints and two intermediate
points. 14
Figure 3 – Three-phase equipment with six terminals . 15
Figure 4 – Three-element equipment with twelve terminals: Six endpoints and six
intermediate points . 15
Figure 5 – Equipment with groups of elements . 16
Figure 6 – Interconnection of equipment terminals and certain designated conductors . 16
Table A.1 – Colours, alphanumeric notations and graphical symbols used for
identification of conductors and terminals . 18
– 4 – IEC 60445:2017 RLV © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –
IDENTIFICATION OF EQUIPMENT TERMINALS,
CONDUCTOR TERMINATIONS AND CONDUCTORS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
This document has been prepared by IEC technical committee 3: Information structures and
elements, identification and marking principles, documentation and graphical symbols.
It has the status of a basic safety publication in accordance with IEC Guide 104.
This sixth edition cancels and replaces the fifth edition of IEC 60445, published in 2010.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the text of the introduction has been moved into the scope in accordance with
IEC Guide 104;
b) colour codes for the identification of line conductors of DC systems;
c) colour code for the identification of functional earthing conductor;
d) update of Table A.1 with colour codes for DC line conductors;
e) conversion of notes containing non-mandatory requirements to normative text;
f) the terminology is aligned with IEC 60050-195.
The text of this International Standard is based on the following documents:
FDIS Report on voting
3/1313/FDIS 3/1326/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The reader's attention is drawn to the fact that Annex B lists all of the “in-some-country”
clauses on differing practices of a less permanent nature relating to the subject of this
standard.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of November 2017 have been included in this copy.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60445:2017 RLV © IEC 2017
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –
IDENTIFICATION OF EQUIPMENT TERMINALS,
CONDUCTOR TERMINATIONS AND CONDUCTORS
1 Scope
This document applies to the identification and marking of terminals of electrical equipment
such as resistors, fuses, relays, contactors, transformers, rotating machines and, wherever
applicable, to combinations of such equipment (e.g. assemblies), and also applies to the
identification of terminations of certain designated conductors. It also provides general rules
for the use of certain colours or alphanumeric notations to identify conductors with the aim of
avoiding ambiguity and ensuring safe operation. These conductor colours or alphanumeric
notations are intended to be applied in cables or cores, busbars, electrical equipment and
installations.
This basic safety publication is primarily intended for use by technical committees in the
preparation of standards in accordance with the principles laid down in IEC Guide 104 and
ISO/IEC Guide 51.
It is not intended for use by manufacturers or certification bodies. One of the responsibilities
of a technical committee is, wherever applicable, to make use of basic safety publications in
the preparation of its publications. The requirements of this basic safety publication will not
apply unless specifically referred to or included in the relevant publications.
In this fifth edition of IEC 60445, the terminology has been aligned with IEC 60050-195.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60417, Graphical symbols for use on equipment
IEC 60617, Graphical symbols for diagrams
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
NOTE The terms are sorted in alphabetical order in the English language.
3.1
electrical equipment
item used for such purposes as generation, conversion, transmission, distribution or utilization
of electric energy, such as electrical machines, transformers, switchgear and controlgear,
measuring instruments, protective devices, wiring systems, current-using equipment, etc.
[SOURCE: IEC 60050-826:2004, 826-16-01, modified]
3.2
functional bonding conductor
conductor provided for functional-equipotential-bonding
[SOURCE: IEC 60050-195:1998, 195-02-16]
3.3
functional earthing
functional grounding (US)
earthing a point or points in a system or in an installation or in equipment, for purposes other
than electrical safety
[SOURCE: IEC 60050-195/AMD1:2001, 195-01-13]
3.4
functional earthing conductor
functional grounding conductor, US
earthing conductor provided for functional earthing
[SOURCE: IEC 60050-195:1998, 195-02-15]
3.5
functional-equipotential-bonding
equipotential bonding for operational reasons other than safety
[SOURCE: IEC 60050-195:1998, 195-01-16]
3.6
line conductor
DEPRECATED: phase conductor (in AC systems)
DEPRECATED: pole conductor (in DC systems)
conductor which is energized in normal operation and capable of contributing to the
transmission or distribution of electric energy but which is not a neutral or mid-point conductor
[SOURCE: IEC 60050-195:1998, 195-02-08]
3.7
mid-point conductor
conductor electrically connected to the mid-point and capable of contributing to the
distribution of electric energy
[SOURCE: IEC 60050-195:1998, 195-02-07]
3.8
neutral conductor
conductor electrically connected to the neutral point and capable of contributing to the
distribution of electric energy
– 8 – IEC 60445:2017 RLV © IEC 2017
[SOURCE: IEC 60050-195:1998, 195-02-06]
3.9
PEL conductor
conductor combining the functions of both a protective earthing conductor and a line
conductor
[SOURCE: IEC 60050-195:1998, 195-02-14]
3.10
PEM conductor
conductor combining the functions of both a protective earthing conductor and a mid-point
conductor
[SOURCE: IEC 60050-195:1998, 195-02-13]
3.11
PEN conductor
conductor combining the functions of both a protective earthing conductor and a neutral
conductor
[SOURCE: IEC 60050-195:1998, 195-02-12]
3.12
protective bonding conductor
DEPRECATED: equipotential bonding conductor
protective conductor provided for protective-equipotential-bonding
[SOURCE: IEC 60050-195:1998, 195-02-10]
3.13
protective bonding conductor earthed
protective bonding conductor with a conductive path to local earth
3.14
protective bonding conductor unearthed
protective bonding conductor without a conductive path to local earth
3.15
protective conductor
(identification: PE)
equipment grounding conductor, US
grounding electrode conductor, US
conductor provided for purposes of safety, for example protection against electric shock
Note 1 to entry: The terms equipment grounding conductor and grounding electrode conductor are used in the US
depending on their application.
[SOURCE: IEC 60050-195:1998, 195-02-09, modified – two synonyms and a note to entry
have been added.]
3.16
protective earthing
protective grounding, US
earthing a point or points in a system or in an installation or in equipment, for purposes of
electrical safety
[SOURCE: IEC 60050-195, Amendment 1:2001, 195-01-11]
3.17
protective earthing conductor
protective grounding conductor, US
protective conductor provided for protective earthing
[SOURCE: IEC 60050-195:1998, 195-02-11]
3.18
protective-equipotential-bonding
equipotential bonding for the purposes of safety
[SOURCE: IEC 60050-195:1998, 195-01-15]
3.19
earth, verb
ground, verb,US
make an electric connection between a given point in a system of in an installation or in
equipment and a local earth
Note 1 to entry: The connection to local earth may be
– intentional, or
– unintentional or accidental
and may be permanent or temporary.
[SOURCE: IEC 60050-195:1998, 195-01-08]
3.20
equipotential bonding
provision of electric connections between conductive parts, intended to achieve
equipotentiality
[SOURCE: IEC 60050-195:1998, 195-01-10]
3.21
equipotentiality
state when conductive parts are at a substantially equal electric potential
[SOURCE: IEC 60050-195:1998, 195-01-09]
4 Methods of identification
Where the identification of equipment terminals and of terminations of certain designated
conductors is considered necessary, it shall be effected by the use of one or more of the
following methods:
– the physical or relative location of the equipment terminals or of terminations of certain
designated conductors;
– a colour code for equipment terminals and terminations of certain designated conductors
in accordance with Clause 6;
– graphical symbols in accordance with IEC 60417. If additional symbols are required, these
shall be consistent with IEC 60617;
– an alphanumeric notation in accordance with the system laid down in Clause 7.
To keep consistency with the documentation, conductor and equipment terminal designation,
the alphanumeric notation is recommended.
– 10 – IEC 60445:2017 RLV © IEC 2017
Identification of conductors by colours shall be in accordance with the requirements provided
in Clause 6. Identification of conductors by alphanumeric notation shall be in accordance with
the requirements provided in Clause 7.
NOTE It is recognised that for complex systems and installations additional marking and labelling may be needed
are used for reasons other than safety, see for example IEC 62491.
5 Application of identification means
The identifying colour, graphical symbol or alphanumeric notation shall be located on, or
adjacent to, the corresponding terminal.
When more than one identification method is used and confusion is possible, the correlation
between the methods shall be clarified in the associated documentation.
When no confusion is possible, the juxtaposition of numerical and alphanumeric notation may
be applied.
Terminals and conductors used for earthing are divided concerning their purpose of earthing
into the two basic concepts of protective earthing and functional earthing.
– If a terminal or conductor fulfils the requirements for both protective earthing and
functional earthing, it shall be designated as a protective earthing terminal or protective
earthing conductor, respectively.
– If the requirements for protective earthing are not met by a functional earthing terminal or
functional earthing conductor, it shall not be marked with an identification of a protective
earthing terminal or protective earthing conductor, respectively.
– The requirements for functional earthing are to be defined by the manufacturer or the
relevant product committee and should be specified within the documentation of the
equipment.
NOTE For example, requirements for handling EMC issues.
6 Identification by colours
6.1 General
For identification of conductors, the following colours are permitted:
BLACK, BROWN, RED, ORANGE, YELLOW, GREEN, BLUE, VIOLET, GREY, WHITE,
PINK, TURQUOISE.
NOTE This list of colours is derived from IEC 60757.
The identification by colour shall be used at terminations and preferably throughout the length
of the conductor either by the colour of the insulation or by colour markers, except for bare
conductors where the colour identification shall be at termination and connection points.
Identification by colour or marking is not required for
– concentric conductors of cables,
– metal sheath or armour of cables when used as a protective conductor,
– bare conductors where permanent identification is not practicable,
– extraneous-conductive-parts used as a protective conductor,
– exposed-conductive-parts used as a protective conductor.
Additional markings, for example alphanumerical, are allowed, provided that the colour
identification remains unambiguous.
6.2 Use of single colours
6.2.1 Permitted colours
The single colours GREEN and YELLOW are only permitted where confusion with the
colouring of the conductors in accordance with 6.3.2 to 6.3.6 is not likely to occur.
6.2.2 Neutral or mid-point conductor
Where a circuit includes a neutral or mid-point conductor identified by colour, the colour used
for this purpose shall be BLUE. In order to avoid confusion with other colours it is
recommended to use an unsaturated colour BLUE, often called "light blue". BLUE shall not be
used for identifying any other conductor where confusion is possible.
In the absence of a neutral or mid-point conductor within the whole wiring system, a conductor
identified by BLUE may be used for any other purposes, except as a protective conductor.
If identification by colour is used, bare conductors used as neutral or mid-point conductors
shall be either coloured by a BLUE stripe, 15 mm to 100 mm wide in each unit or enclosure
and each accessible position, or coloured BLUE throughout their length.
NOTE In IEC 60079-11 prescribes blue when a , the colour BLUE is used for the marking by colour of terminals,
terminal boxes, plugs and sockets of intrinsically-safe circuits.
6.2.3 Line conductor in AC system
For line conductors in AC systems the preferred colours are BLACK, BROWN and GREY.
NOTE The sequence of colour codes in 6.2.3 is alphabetical, and does not recommend indicate any preferred
phasing or direction of rotation.
6.2.4 Line conductor in DC system
For line conductors in DC systems the preferred colours are:
– RED for the positive line conductor,
– WHITE for the negative line conductor.
6.2.5 Functional earthing conductor
For colour marking of a functional earthing conductor the preferred colour is PINK. The colour
need only be applied at the terminations and at points of connection.
6.3 Use of bi-colour combinations
6.3.1 Permitted colours
Combinations of any two of the colours listed in 6.1 are permitted provided there is no risk of
confusion.
To avoid such confusion, the colour GREEN and the colour YELLOW shall not be used in
colour combinations other than the combination GREEN-AND-YELLOW.
The use of The colour combination of the colours GREEN-AND-YELLOW is restricted to the
purposes of 6.3.2 to 6.3.6.
6.3.2 Protective conductor
The protective conductor shall be identified by the bi-colour combination GREEN-AND-
YELLOW.
– 12 – IEC 60445:2017 RLV © IEC 2017
NOTE 1 It may be necessary to provide additional marking to unambiguously identify a certain designated
conductor.
NOTE 2 An additional colour marking is required for PEN, PEL and PEM conductors.
GREEN-AND-YELLOW is the only colour combination recognized for identifying the protective
conductor.
For a PEN, PEM, and PEL conductor, additional requirements are given in 6.3.3 to 6.3.5
The colour combination GREEN-AND-YELLOW shall be such that, on any 15 mm length of the
conductor where colour coding is applied, one of these colours covers at least 30 % and not
more than 70 % of the surface of the conductor, the other colour covering the remainder of
that surface.
If bare conductors, used as protective conductors, are provided with colouring they shall be
coloured GREEN-AND-YELLOW, either throughout the whole length of each conductor or in
each compartment or unit or at each accessible position. If adhesive tape is used, only bi-
coloured GREEN-AND-YELLOW tape shall be applied.
NOTE 3 Where the protective conductor can be easily identified by its shape, construction or
position, for example a concentric conductor, colour coding throughout its length is not
necessary but the ends or accessible positions should be clearly identified by the graphical
symbol IEC 60417-5019 (2006-08) "Protective earth; protective ground", , or the bi-colour
combination GREEN-AND-YELLOW or the alphanumeric notation PE.
NOTE 4 If extraneous conductive parts are used as a PE conductor identification by colours is
not necessary.
6.3.3 PEN conductor
A PEN conductor, when insulated, shall be marked by one of the following methods:
– GREEN-AND-YELLOW throughout its length with, in addition, BLUE markings at the
terminations and points of connection; or
– BLUE throughout its length with, in addition, GREEN-AND-YELLOW markings at the
terminations and points of connection.
NOTE 1 The choice of method or methods to be applied within a country should be made
decided by the relevant National Committee and not on an individual basis.
NOTE 2 The additional BLUE markings at the termination and points of connection may be
omitted once either of the following two indents conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
6.3.4 PEL conductor
A PEL conductor, when insulated, shall be marked GREEN-AND-YELLOW throughout its
length with, in addition, BLUE markings at its terminations and points of connection of the
PEL conductor.
NOTE The additional BLUE markings at the termination and points of connection may be
omitted once either of the following two indents conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
If confusion with a PEN or PEM conductor is likely, the alphanumeric designation as given in
7.3.5 shall be indicated at their terminations and points of connection.
6.3.5 PEM conductor
A PEM conductor, when insulated, shall be marked GREEN-AND-YELLOW throughout its
length with, in addition, BLUE markings at its terminations and points of connection of the
PEM conductor.
NOTE The additional BLUE markings at the termination and points of connection may be
omitted once either of the following two indents conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
If confusion with a PEN or PEL conductor is likely, the alphanumeric designation as given in
7.3.6 shall be indicated at their terminations.
6.3.6 Protective bonding conductor
A protective bonding conductor shall be identified by the bi-colour combination GREEN-AND-
YELLOW as specified in 6.3.1.
7 Identification by alphanumeric notation
7.1 General
If letters and/or numerals are used for identification, letters shall be upper case Latin
characters only and numerals shall be Arabic numerals.
NOTE It is recommended that the reference letters for DC elements be chosen from the first
part and reference letters for AC elements from the second part of the alphabet.
Letters “I” and “O” shall not be used for identification to prevent confusion with the numerals
“1” and “0”; the alphanumeric signs “+” and “–“ may be used.
In order to avoid confusion, unattached numerals 6 and 9 shall be underlined.
All alphanumeric notations shall be in strong contrast to the colour of the insulation.
The alphanumeric identification shall be clearly legible and durable.
NOTE For evaluation of the durability, see IEC 60227-2.
The alphanumeric system applies to identification of conductors and of conductors in a group
of conductors. Conductors with GREEN-AND-YELLOW coloured insulation shall only be
identified as a certain designated conductor in accordance with 7.3.3 to 7.3.9.
The alphanumeric identifications specified in 7.3 shall not be used for any other purpose than
that specified.
Where no confusion is possible, parts of the complete alphanumeric notation laid down in the
following marking principles may be omitted.
– 14 – IEC 60445:2017 RLV © IEC 2017
7.2 Equipment terminal identification – Marking principles
7.2.1 Marking of equipment terminals is (or should be) based on the principles provided in
7.2.2 to 7.2.5:
7.2.2 The two end points of an element are distinguished by consecutive reference
numbers, the odd number being lower than the even number, for example 1 and 2
(see Figure 1).
IEC
Figure 1 – Single element with two terminals
7.2.3 The intermediate points of a single element are distinguished by reference numbers,
preferably in a numerical order, for example 3, 4, 5, etc. The reference numbers chosen for
intermediate points shall be higher than those chosen for the end points; their numbering
commences at the point which lies closest to the end point with the lower reference number.
Thus, for example, the intermediate points, of an element with the end points 1 and 2 will be
denoted by the reference numbers 3 and 4 (see Figure 2).
IEC
Figure 2 – Single element with four terminals: Two endpoints
and two intermediate points
7.2.4 If several similar elements are combined in a group of elements, then one of the
following methods for marking the elements shall be used:
– the two end points and intermediate points, if any, are distinguished by letters preceding
the reference numbers referred to in 7.2.2 and 7.2.3, for example U, V, W corresponding
to the phases of a three-phase AC system (see Figure 3);
IEC
Figure 3 – Three-phase equipment with six terminals
– the two end points and intermediate points, if any, are distinguished by numbers preceding
the reference numbers referred to in 7.2.2 and 7.2.3 where a phase identification is not
necessary or possible. To avoid confusion these numbers shall be separated by a full
stop. For example the end points of one element may be marked 1.1 and 1.2, those of
another element 2.1 and 2.2 (see Figure 4);
NOTE For examples of an unambiguous terminal designation with respect to the object to which the terminal
belongs, see IEC 61666:2010, Annex A.
IEC
Figure 4 – Three-element equipment with twelve terminals:
Six endpoints and six intermediate points
– in case of terminal blocks, numerical identification in numerical order.
Further detailed requirements on terminal markings and identification may be given by
relevant product committees.
7.2.5 Similar groups of elements having the same reference letters are distinguished by a
numerical prefix to the reference letters (see Figure 5a and Figure 5b)).
– 16 – IEC 60445:2017 RLV © IEC 2017
IEC IEC
a) Three-phase equipment b) Two-phase equipment with two groups of
with two groups of elements elements with four terminals each not intended to
be connected to certain designated conductors
Figure 5 – Equipment with groups of elements
Figure 6 illustrates the interconnection of equipment terminals and certain designated
conductors, marked in accordance with the alphanumeric notation.
IEC
Figure 6 – Interconnection of equipment terminals and certain designated conductors
7.3 Identification of certain designated conductors
7.3.1 General
Equipment terminals which are intended to be connected directly or indirectly to certain
designated conductors, and terminations of certain designated conductors shall be marked
with reference letters or graphical symbols or both reference letters and graphical symbols
according to Table A.1.
7.3.2 Neutral conductor
The alphanumeric identification of a neutral conductor shall be ‘N’.
7.3.3 Protective conductor
The alphanumeric identification of a protective conductor shall be ‘PE’. This identification also
applies for a protective earthing conductor.
7.3.4 PEN conductor
The alphanumeric identification of a PEN conductor shall be ‘PEN’.
7.3.5 PEL conductor
The alphanumeric identification of a PEL conductor shall be ‘PEL’.
7.3.6 PEM conductor
The alphanumeric identification of a PEM conductor shall be ‘PEM’.
7.3.7 Protective bonding conductor
The alphanumeric identification of a protective bonding conductor shall be ‘PB’.
7.3.8 Protective bonding conductor earthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor earthed shall be ‘PBE’.
7.3.9 Protective bonding conductor unearthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor unearthed shall be ‘PBU’.
7.3.10 Functional earthing conductor
The alphanumeric identification of a functional earthing conductor shall be ‘FE’.
7.3.11 Functional bonding conductor
The alphanumeric identification of a functional bonding conductor shall be ‘FB’.
7.3.12 Mid-point conductor
The alphanumeric identification of a mid-point conductor shall be ‘M’.
7.3.13 Line conductor
The alphanumeric identification of a line conductor shall start with the letter “L” suffixed by:
– for an AC circuit, a sequential number of line conductors, starting with the digit one “1”;
– for a DC circuit, with the sign “+” for the positive line conductor and with the sign “-“ for the
negative line conductor.
If no more than one line conductor is used, the suffix may be omitted.
– 18 – IEC 60445:2017 RLV © IEC 2017
Annex A
(informative)
Colours, alphanumeric notations and graphical symbols
used for identification of conductors and terminals
Table A.1 – Colours, alphanumeric notations and graphical symbols used
for identification of conductors and terminals
Identification of conductors / terminals by
a
Designated conductors/terminals Alphanumeric notations
Graphical
Colours
b
symbols
Conductors Terminals
AC conductors AC AC -
d
Line 1 L1 U BK or
c d
Line 2 L2 V BN or
c d
Line 3 L3 W GY
Mid-point conductor M M
No
e
BU
recommendation
Neutral conductor N N
DC conductors DC DC -
Positive
L+ + RD
Negative L- - WH
Mid-point conductor M M No
e
BU recommendation
Neutral conductor N N
Protective conductor
PE PE GNYE
PEN conductor PEN PEN No
f
GNYE recommendation
PEL conductor PEL PEL
f
BU
PEM conductor PEM PEM
g
Protective bonding conductor PB PB
GNYE
– earthed
PBE PBE No
recommendation
– unearthed
PBU PBU
h
Functional earthing conductor
FE FE PK
Functional bonding conductor
No
FB FB
recommendation
a
See Clause 7.
b
The graphics shown correspond to the following symbol No in IEC 60417.
IEC 60417-5032 (2002-10) IEC 60417-5019 (2006-08)
IEC 60417-5031 (2002-10) IEC 60417-5018 (2006-10)
IEC 60417-5005 (2002-10) IEC 60417-5020 (2002-10)
IEC 60417-5006 (2002-10) IEC 60417-5021 (2002-10)
c
Only necessary in systems with more than one phase.
d
This sequence of colour codes is alphabetical. It does not represent recommended phasing or a direction of
rotation.
e
See 6.2.2.
f
See 6.3.3 to 6.3.5.
g
A protective bonding conductor will in most cases be a protective bonding conductor earthed. It is not
necessary to designate it with PBE. In those cases where a distinction between a protective bonding
conductor earthed and a protective bonding conductor unearthed is used, a clear distinction between them
shall be made (for example, within electro-medical installations) and the designations PBE and PBU should
be applied.
h
Neither the designation FE nor the graphical symbol 5018 of IEC 60417 shall be applied for conductors or
terminals having a protective function. Bi-colour insulation GREEN-AND-YELLOW cannot be used for
conductors that do not have a protective function (i.e. for conductors other than PE, PEN, PEL, PEM, PB,
PBE, PBU). See Clause 5.
– 20 – IEC 60445:2017 RLV © IEC 2017
Annex B
(informative)
List of notes concerning certain countries
Country Clause/su Nature (permanent or less permanent Rationale (detailed justification for Wording
bclause according to IEC Directives) the requested country note)
No.
RU 3 The earthed line conductor is used in In the Russian Federation, the following definitions apply:
single-phase AC electrical systems, in
earthed line conductor
three-phase AC electrical systems
line conductor which has an electrical connection with the earth
without the neutral point and in two-wire
electrode
DC electrical systems.
phase conductor
In the Russian Federation use of terms
line conductor which is used in an AC electrical circuit
"phase conductor" and “pole conductor”
has been renewed tom indicate are used
pole conduc
...
IEC 60445 ®
Edition 6.0 2017-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Basic and safety principles for man-machine interface, marking and
identification – Identification of equipment terminals, conductor terminations
and conductors
Principes fondamentaux et de sécurité pour les interfaces homme-machine,
le marquage et l’identification – Identification des bornes de matériels, des
extrémités de conducteurs et des conducteurs
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IEC 60445 ®
Edition 6.0 2017-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Basic and safety principles for man-machine interface, marking and
identification – Identification of equipment terminals, conductor terminations
and conductors
Principes fondamentaux et de sécurité pour les interfaces homme-machine,
le marquage et l’identification – Identification des bornes de matériels, des
extrémités de conducteurs et des conducteurs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 01.080.20; 13.110; 29.020 ISBN 978-2-8322-4577-4
– 2 – IEC 60445:2017 © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Methods of identification . 9
5 Application of identification means . 10
6 Identification by colours . 10
6.1 General . 10
6.2 Use of single colours . 11
6.2.1 Permitted colours. 11
6.2.2 Neutral or mid-point conductor . 11
6.2.3 Line conductor in AC system . 11
6.2.4 Line conductor in DC system . 11
6.2.5 Functional earthing conductor . 11
6.3 Use of bi-colour combinations . 11
6.3.1 Permitted colours. 11
6.3.2 Protective conductor . 11
6.3.3 PEN conductor . 12
6.3.4 PEL conductor . 12
6.3.5 PEM conductor . 13
6.3.6 Protective bonding conductor. 13
7 Identification by alphanumeric notation . 13
7.1 General . 13
7.2 Equipment terminal identification – Marking principles . 14
7.3 Identification of certain designated conductors . 16
7.3.1 General . 16
7.3.2 Neutral conductor . 16
7.3.3 Protective conductor . 16
7.3.4 PEN conductor . 17
7.3.5 PEL conductor . 17
7.3.6 PEM conductor . 17
7.3.7 Protective bonding conductor. 17
7.3.8 Protective bonding conductor earthed . 17
7.3.9 Protective bonding conductor unearthed . 17
7.3.10 Functional earthing conductor . 17
7.3.11 Functional bonding conductor . 17
7.3.12 Mid-point conductor . 17
7.3.13 Line conductor . 17
Annex A (informative) Colours, alphanumeric notations and graphical symbols used
for identification of conductors and terminals . 18
Annex B (informative) List of notes concerning certain countries . 20
Bibliography . 26
Figure 1 – Single element with two terminals . 14
Figure 2 – Single element with four terminals: Two endpoints and two intermediate
points. 14
Figure 3 – Three-phase equipment with six terminals . 15
Figure 4 – Three-element equipment with twelve terminals: Six endpoints and six
intermediate points . 15
Figure 5 – Equipment with groups of elements . 16
Figure 6 – Interconnection of equipment terminals and certain designated conductors . 16
Table A.1 – Colours, alphanumeric notations and graphical symbols used for
identification of conductors and terminals . 18
– 4 – IEC 60445:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –
IDENTIFICATION OF EQUIPMENT TERMINALS,
CONDUCTOR TERMINATIONS AND CONDUCTORS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared by IEC technical committee 3: Information structures and
elements, identification and marking principles, documentation and graphical symbols.
It has the status of a basic safety publication in accordance with IEC Guide 104.
This sixth edition cancels and replaces the fifth edition of IEC 60445, published in 2010.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the text of the introduction has been moved into the scope in accordance with
IEC Guide 104;
b) colour codes for the identification of line conductors of DC systems;
c) colour code for the identification of functional earthing conductor;
d) update of Table A.1 with colour codes for DC line conductors;
e) conversion of notes containing non-mandatory requirements to normative text;
f) the terminology is aligned with IEC 60050-195.
The text of this International Standard is based on the following documents:
FDIS Report on voting
3/1313/FDIS 3/1326/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The reader's attention is drawn to the fact that Annex B lists all of the “in-some-country”
clauses on differing practices of a less permanent nature relating to the subject of this
standard.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of November 2017 have been included in this copy.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60445:2017 © IEC 2017
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –
IDENTIFICATION OF EQUIPMENT TERMINALS,
CONDUCTOR TERMINATIONS AND CONDUCTORS
1 Scope
This document applies to the identification and marking of terminals of electrical equipment
such as resistors, fuses, relays, contactors, transformers, rotating machines and, wherever
applicable, to combinations of such equipment (e.g. assemblies), and also applies to the
identification of terminations of certain designated conductors. It also provides general rules
for the use of certain colours or alphanumeric notations to identify conductors with the aim of
avoiding ambiguity and ensuring safe operation. These conductor colours or alphanumeric
notations are intended to be applied in cables or cores, busbars, electrical equipment and
installations.
This basic safety publication is primarily intended for use by technical committees in the
preparation of standards in accordance with the principles laid down in IEC Guide 104 and
ISO/IEC Guide 51.
It is not intended for use by manufacturers or certification bodies. One of the responsibilities
of a technical committee is, wherever applicable, to make use of basic safety publications in
the preparation of its publications. The requirements of this basic safety publication will not
apply unless specifically referred to or included in the relevant publications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60417, Graphical symbols for use on equipment
IEC 60617, Graphical symbols for diagrams
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
NOTE The terms are sorted in alphabetical order in the English language.
3.1
electric equipment
item used for such purposes as generation, conversion, transmission, distribution or utilization
of electric energy, such as electric machines, transformers, switchgear and controlgear,
measuring instruments, protective devices, wiring systems, current-using equipment
[SOURCE: IEC 60050-826:2004, 826-16-01]
3.2
functional bonding conductor
conductor provided for functional-equipotential-bonding
[SOURCE: IEC 60050-195:1998, 195-02-16]
3.3
functional earthing
functional grounding (US)
earthing a point or points in a system or in an installation or in equipment, for purposes other
than electrical safety
[SOURCE: IEC 60050-195/AMD1:2001, 195-01-13]
3.4
functional earthing conductor
functional grounding conductor, US
earthing conductor provided for functional earthing
[SOURCE: IEC 60050-195:1998, 195-02-15]
3.5
functional-equipotential-bonding
equipotential bonding for operational reasons other than safety
[SOURCE: IEC 60050-195:1998, 195-01-16]
3.6
line conductor
DEPRECATED: phase conductor (in AC systems)
DEPRECATED: pole conductor (in DC systems)
conductor which is energized in normal operation and capable of contributing to the
transmission or distribution of electric energy but which is not a neutral or mid-point conductor
[SOURCE: IEC 60050-195:1998, 195-02-08]
3.7
mid-point conductor
conductor electrically connected to the mid-point and capable of contributing to the
distribution of electric energy
[SOURCE: IEC 60050-195:1998, 195-02-07]
3.8
neutral conductor
conductor electrically connected to the neutral point and capable of contributing to the
distribution of electric energy
[SOURCE: IEC 60050-195:1998, 195-02-06]
– 8 – IEC 60445:2017 © IEC 2017
3.9
PEL conductor
conductor combining the functions of both a protective earthing conductor and a line
conductor
[SOURCE: IEC 60050-195:1998, 195-02-14]
3.10
PEM conductor
conductor combining the functions of both a protective earthing conductor and a mid-point
conductor
[SOURCE: IEC 60050-195:1998, 195-02-13]
3.11
PEN conductor
conductor combining the functions of both a protective earthing conductor and a neutral
conductor
[SOURCE: IEC 60050-195:1998, 195-02-12]
3.12
protective bonding conductor
DEPRECATED: equipotential bonding conductor
protective conductor provided for protective-equipotential-bonding
[SOURCE: IEC 60050-195:1998, 195-02-10]
3.13
protective bonding conductor earthed
protective bonding conductor with a conductive path to local earth
3.14
protective bonding conductor unearthed
protective bonding conductor without a conductive path to local earth
3.15
protective conductor
(identification: PE)
equipment grounding conductor, US
grounding electrode conductor, US
conductor provided for purposes of safety, for example protection against electric shock
Note 1 to entry: The terms equipment grounding conductor and grounding electrode conductor are used in the US
depending on their application.
[SOURCE: IEC 60050-195:1998, 195-02-09, modified – two synonyms and a note to entry
have been added.]
3.16
protective earthing
protective grounding, US
earthing a point or points in a system or in an installation or in equipment, for purposes of
electrical safety
[SOURCE: IEC 60050-195:2001, 195-01-11]
3.17
protective earthing conductor
protective grounding conductor, US
protective conductor provided for protective earthing
[SOURCE: IEC 60050-195:1998, 195-02-11]
3.18
protective-equipotential-bonding
equipotential bonding for the purposes of safety
[SOURCE: IEC 60050-195:1998, 195-01-15]
3.19
earth, verb
ground, verb,US
make an electric connection between a given point in a system of in an installation or in
equipment and a local earth
Note 1 to entry: The connection to local earth may be
– intentional, or
– unintentional or accidental
and may be permanent or temporary.
[SOURCE: IEC 60050-195:1998, 195-01-08]
3.20
equipotential bonding
provision of electric connections between conductive parts, intended to achieve
equipotentiality
[SOURCE: IEC 60050-195:1998, 195-01-10]
3.21
equipotentiality
state when conductive parts are at a substantially equal electric potential
[SOURCE: IEC 60050-195:1998, 195-01-09]
4 Methods of identification
Where the identification of equipment terminals and of terminations of certain designated
conductors is considered necessary, it shall be effected by the use of one or more of the
following methods:
– the physical or relative location of the equipment terminals or of terminations of certain
designated conductors;
– a colour code for equipment terminals and terminations of certain designated conductors
in accordance with Clause 6;
– graphical symbols in accordance with IEC 60417. If additional symbols are required, these
shall be consistent with IEC 60617;
– an alphanumeric notation in accordance with the system laid down in Clause 7.
To keep consistency with the documentation, conductor and equipment terminal designation,
the alphanumeric notation is recommended.
– 10 – IEC 60445:2017 © IEC 2017
Identification of conductors by colours shall be in accordance with the requirements provided
in Clause 6. Identification of conductors by alphanumeric notation shall be in accordance with
the requirements provided in Clause 7.
NOTE It is recognised that for complex systems and installations additional marking and labelling are used for
reasons other than safety, see for example IEC 62491.
5 Application of identification means
The identifying colour, graphical symbol or alphanumeric notation shall be located on, or
adjacent to, the corresponding terminal.
When more than one identification method is used and confusion is possible, the correlation
between the methods shall be clarified in the associated documentation.
When no confusion is possible, the juxtaposition of numerical and alphanumeric notation may
be applied.
Terminals and conductors used for earthing are divided concerning their purpose of earthing
into the two basic concepts of protective earthing and functional earthing.
– If a terminal or conductor fulfils the requirements for both protective earthing and
functional earthing, it shall be designated as a protective earthing terminal or protective
earthing conductor, respectively.
– If the requirements for protective earthing are not met by a functional earthing terminal or
functional earthing conductor, it shall not be marked with an identification of a protective
earthing terminal or protective earthing conductor, respectively.
– The requirements for functional earthing are to be defined by the manufacturer or the
relevant product committee and should be specified within the documentation of the
equipment.
NOTE For example, requirements for handling EMC issues.
6 Identification by colours
6.1 General
For identification of conductors, the following colours are permitted:
BLACK, BROWN, RED, ORANGE, YELLOW, GREEN, BLUE, VIOLET, GREY, WHITE,
PINK, TURQUOISE.
NOTE This list of colours is derived from IEC 60757.
The identification by colour shall be used at terminations and preferably throughout the length
of the conductor either by the colour of the insulation or by colour markers, except for bare
conductors where the colour identification shall be at termination and connection points.
Identification by colour or marking is not required for
– concentric conductors of cables,
– metal sheath or armour of cables when used as a protective conductor,
– bare conductors where permanent identification is not practicable,
– extraneous-conductive-parts used as a protective conductor,
– exposed-conductive-parts used as a protective conductor.
Additional markings, for example alphanumerical, are allowed, provided that the colour
identification remains unambiguous.
6.2 Use of single colours
6.2.1 Permitted colours
The single colours GREEN and YELLOW are only permitted where confusion with the
colouring of the conductors in accordance with 6.3.2 to 6.3.6 is not likely to occur.
6.2.2 Neutral or mid-point conductor
Where a circuit includes a neutral or mid-point conductor identified by colour, the colour used
for this purpose shall be BLUE. In order to avoid confusion with other colours it is
recommended to use an unsaturated colour BLUE, often called "light blue". BLUE shall not be
used for identifying any other conductor where confusion is possible.
In the absence of a neutral or mid-point conductor within the whole wiring system, a conductor
identified by BLUE may be used for any other purposes, except as a protective conductor.
If identification by colour is used, bare conductors used as neutral or mid-point conductors
shall be either coloured by a BLUE stripe, 15 mm to 100 mm wide in each unit or enclosure
and each accessible position, or coloured BLUE throughout their length.
NOTE In IEC 60079-11, the colour BLUE is used for the marking by colour of terminals, terminal boxes, plugs and
sockets of intrinsically-safe circuits.
6.2.3 Line conductor in AC system
For line conductors in AC systems the preferred colours are BLACK, BROWN and GREY.
NOTE The sequence of colour codes in 6.2.3 is alphabetical, and does not indicate any preferred phasing or
direction of rotation.
6.2.4 Line conductor in DC system
For line conductors in DC systems the preferred colours are:
– RED for the positive line conductor,
– WHITE for the negative line conductor.
6.2.5 Functional earthing conductor
For colour marking of a functional earthing conductor the preferred colour is PINK. The colour
need only be applied at the terminations and at points of connection.
6.3 Use of bi-colour combinations
6.3.1 Permitted colours
Combinations of any two of the colours listed in 6.1 are permitted provided there is no risk of
confusion.
To avoid such confusion, the colour GREEN and the colour YELLOW shall not be used in
colour combinations other than the combination GREEN-AND-YELLOW.
The colour combination GREEN-AND-YELLOW is restricted to the purposes of 6.3.2 to 6.3.6.
6.3.2 Protective conductor
The protective conductor shall be identified by the bi-colour combination GREEN-AND-
YELLOW.
– 12 – IEC 60445:2017 © IEC 2017
GREEN-AND-YELLOW is the only colour combination recognized for identifying the protective
conductor.
For a PEN, PEM, and PEL conductor, additional requirements are given in 6.3.3 to 6.3.5
The colour combination GREEN-AND-YELLOW shall be such that, on any 15 mm length of the
conductor where colour coding is applied, one of these colours covers at least 30 % and not
more than 70 % of the surface of the conductor, the other colour covering the remainder of
that surface.
If bare conductors, used as protective conductors, are provided with colouring they shall be
coloured GREEN-AND-YELLOW, either throughout the whole length of each conductor or in
each compartment or unit or at each accessible position. If adhesive tape is used, only bi-
coloured GREEN-AND-YELLOW tape shall be applied.
Where the protective conductor can be easily identified by its shape, construction or position,
for example a concentric conductor, colour coding throughout its length is not necessary but
the ends or accessible positions should be clearly identified by the graphical symbol
IEC 60417-5019 (2006-08) "Protective earth; protective ground", , or the bi-colour
combination GREEN-AND-YELLOW or the alphanumeric notation PE.
If extraneous conductive parts are used as a PE conductor identification by colours is not
necessary.
6.3.3 PEN conductor
A PEN conductor, when insulated, shall be marked by one of the following methods:
– GREEN-AND-YELLOW throughout its length with, in addition, BLUE markings at the
terminations and points of connection; or
– BLUE throughout its length with, in addition, GREEN-AND-YELLOW markings at the
terminations and points of connection.
The method to be applied within a country should be decided by the National Committee and
not on an individual basis.
The additional BLUE markings at the termination and points of connection may be omitted
once either of the following two conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
6.3.4 PEL conductor
A PEL conductor, when insulated, shall be marked GREEN-AND-YELLOW throughout its
length with, in addition, BLUE markings at its terminations and points of connection of the
PEL conductor.
The additional BLUE markings at the termination and points of connection may be omitted
once either of the following two conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
If confusion with a PEN or PEM conductor is likely, the alphanumeric designation as given in
7.3.5 shall be indicated at their terminations and points of connection.
6.3.5 PEM conductor
A PEM conductor, when insulated, shall be marked GREEN-AND-YELLOW throughout its
length with, in addition, BLUE markings at its terminations and points of connection of the
PEM conductor.
The additional BLUE markings at the termination and points of connection may be omitted
once either of the following two conditions is met:
– in electric equipment, if relevant requirements are included in specific product standards
or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant
committee.
If confusion with a PEN or PEL conductor is likely, the alphanumeric designation as given in
7.3.6 shall be indicated at their terminations.
6.3.6 Protective bonding conductor
A protective bonding conductor shall be identified by the bi-colour combination GREEN-AND-
YELLOW as specified in 6.3.1.
7 Identification by alphanumeric notation
7.1 General
If letters and/or numerals are used for identification, letters shall be upper case Latin
characters only and numerals shall be Arabic numerals.
It is recommended that the reference letters for DC elements be chosen from the first part and
reference letters for AC elements from the second part of the alphabet.
Letters “I” and “O” shall not be used for identification to prevent confusion with the numerals
“1” and “0”; the alphanumeric signs “+” and “–“ may be used.
In order to avoid confusion, unattached numerals 6 and 9 shall be underlined.
All alphanumeric notations shall be in strong contrast to the colour of the insulation.
The alphanumeric identification shall be clearly legible and durable.
NOTE For evaluation of the durability, see IEC 60227-2.
The alphanumeric system applies to identification of conductors and of conductors in a group
of conductors. Conductors with GREEN-AND-YELLOW coloured insulation shall only be
identified as a certain designated conductor in accordance with 7.3.3 to 7.3.9.
The alphanumeric identifications specified in 7.3 shall not be used for any other purpose than
that specified.
Where no confusion is possible, parts of the complete alphanumeric notation laid down in the
following marking principles may be omitted.
– 14 – IEC 60445:2017 © IEC 2017
7.2 Equipment terminal identification – Marking principles
7.2.1 Marking of equipment terminals is (or should be) based on the principles provided in
7.2.2 to 7.2.5:
7.2.2 The two end points of an element are distinguished by consecutive reference
numbers, the odd number being lower than the even number, for example 1 and 2
(see Figure 1).
IEC
Figure 1 – Single element with two terminals
7.2.3 The intermediate points of a single element are distinguished by reference numbers,
preferably in a numerical order, for example 3, 4, 5, etc. The reference numbers chosen for
intermediate points shall be higher than those chosen for the end points; their numbering
commences at the point which lies closest to the end point with the lower reference number.
Thus, for example, the intermediate points, of an element with the end points 1 and 2 will be
denoted by the reference numbers 3 and 4 (see Figure 2).
IEC
Figure 2 – Single element with four terminals: Two endpoints
and two intermediate points
7.2.4 If several similar elements are combined in a group of elements, then one of the
following methods for marking the elements shall be used:
– the two end points and intermediate points, if any, are distinguished by letters preceding
the reference numbers referred to in 7.2.2 and 7.2.3, for example U, V, W corresponding
to the phases of a three-phase AC system (see Figure 3);
IEC
Figure 3 – Three-phase equipment with six terminals
– the two end points and intermediate points, if any, are distinguished by numbers preceding
the reference numbers referred to in 7.2.2 and 7.2.3 where a phase identification is not
necessary or possible. To avoid confusion these numbers shall be separated by a full
stop. For example the end points of one element may be marked 1.1 and 1.2, those of
another element 2.1 and 2.2 (see Figure 4);
NOTE For examples of an unambiguous terminal designation with respect to the object to which the terminal
belongs, see IEC 61666:2010, Annex A.
IEC
Figure 4 – Three-element equipment with twelve terminals:
Six endpoints and six intermediate points
– in case of terminal blocks, numerical identification in numerical order.
Further detailed requirements on terminal markings and identification may be given by
relevant product committees.
7.2.5 Similar groups of elements having the same reference letters are distinguished by a
numerical prefix to the reference letters (see Figure 5a and Figure 5b)).
– 16 – IEC 60445:2017 © IEC 2017
IEC IEC
a) Three-phase equipment b) Two-phase equipment with two groups of
with two groups of elements elements with four terminals each not intended to
be connected to certain designated conductors
Figure 5 – Equipment with groups of elements
Figure 6 illustrates the interconnection of equipment terminals and certain designated
conductors, marked in accordance with the alphanumeric notation.
IEC
Figure 6 – Interconnection of equipment terminals and certain designated conductors
7.3 Identification of certain designated conductors
7.3.1 General
Equipment terminals which are intended to be connected directly or indirectly to certain
designated conductors, and terminations of certain designated conductors shall be marked
with reference letters or graphical symbols or both reference letters and graphical symbols
according to Table A.1.
7.3.2 Neutral conductor
The alphanumeric identification of a neutral conductor shall be ‘N’.
7.3.3 Protective conductor
The alphanumeric identification of a protective conductor shall be ‘PE’. This identification also
applies for a protective earthing conductor.
7.3.4 PEN conductor
The alphanumeric identification of a PEN conductor shall be ‘PEN’.
7.3.5 PEL conductor
The alphanumeric identification of a PEL conductor shall be ‘PEL’.
7.3.6 PEM conductor
The alphanumeric identification of a PEM conductor shall be ‘PEM’.
7.3.7 Protective bonding conductor
The alphanumeric identification of a protective bonding conductor shall be ‘PB’.
7.3.8 Protective bonding conductor earthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor earthed shall be ‘PBE’.
7.3.9 Protective bonding conductor unearthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor unearthed shall be ‘PBU’.
7.3.10 Functional earthing conductor
The alphanumeric identification of a functional earthing conductor shall be ‘FE’.
7.3.11 Functional bonding conductor
The alphanumeric identification of a functional bonding conductor shall be ‘FB’.
7.3.12 Mid-point conductor
The alphanumeric identification of a mid-point conductor shall be ‘M’.
7.3.13 Line conductor
The alphanumeric identification of a line conductor shall start with the letter “L” suffixed by:
– for an AC circuit, a sequential number of line conductors, starting with the digit one “1”;
– for a DC circuit, with the sign “+” for the positive line conductor and with the sign “-“ for the
negative line conductor.
If no more than one line conductor is used, the suffix may be omitted.
– 18 – IEC 60445:2017 © IEC 2017
Annex A
(informative)
Colours, alphanumeric notations and graphical symbols
used for identification of conductors and terminals
Table A.1 – Colours, alphanumeric notations and graphical symbols
used for identification of conductors and terminals
Identification of conductors / terminals by
a
Designated conductors/terminals Alphanumeric notations
Graphical
Colours
b
symbols
Conductors Terminals
AC conductors AC AC -
d
Line 1 L1 U BK or
c d
Line 2 L2 V BN or
c d
Line 3 L3 W GY
Mid-point conductor M M
No
e
BU
recommendation
Neutral conductor N N
DC conductors DC DC -
Positive
L+ + RD
Negative L- - WH
Mid-point conductor M M No
e
BU recommendation
Neutral conductor N N
Protective conductor
PE PE GNYE
PEN conductor PEN PEN No
f
GNYE recommendation
PEL conductor PEL PEL
f
BU
PEM conductor PEM PEM
g
Protective bonding conductor PB PB
GNYE
– earthed
PBE PBE No
recommendation
– unearthed
PBU PBU
h
Functional earthing conductor
FE FE PK
Functional bonding conductor
No
FB FB
recommendation
a
See Clause 7.
b
The graphics shown correspond to the following symbol No in IEC 60417.
IEC 60417-5032 (2002-10) IEC 60417-5019 (2006-08)
IEC 60417-5031 (2002-10) IEC 60417-5018 (2006-10)
IEC 60417-5005 (2002-10) IEC 60417-5020 (2002-10)
IEC 60417-5006 (2002-10)
...
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